The latest official patch is version 1.3, which can be found here. Note that the digital releases are fully updated, thus the update file is unnecessary on said version. An unofficial 1.4m is also available for download here. The original thread where it was discussed and created (download link dead) can be found here. There is also a 1.4n patch here, which is slightly newer than 1.4m. Note that 1.4n requires 1.4m to be installed first.
In addition to the above there is a fix that adds Gravis UltraSound support available here. For more info on getting GUS working, see DOSBox. A map editor is also available here.

Localizations

Multiplayer types

A fan made "multiplayer project" was once attempted but later abandoned. After a server failure on the mods original host site, a map editor (same one listed in essential improvements) is all that remains of the project.[5][6][7]

Notes

↑ 1.01.1File/folder structure within this directory reflects the path(s) listed for Windows and/or Steam game data (use Wine regedit to access Windows registry paths). Games with Steam Cloud support may store data in ~/.steam/steam/userdata/<user-id>/410970/ in addition to or instead of this directory. The app ID (410970) may differ in some cases. Treat backslashes as forward slashes. See the glossary page for details.